25-10-2017, 11:48 PM
OK, so it seems like there might be a problem with T3. It might be the transistor itself, or it might be something else in the vicinity. It's late now, so I'll reply more fully tomorrow...
Oh, and a correction. Earlier I said 455kHz, but should have said 470kHz. Later sets used 455kHz. But if you're using the Velleman signal tracer (K7000?), then that probably makes little difference at this stage.
Oh, and a correction. Earlier I said 455kHz, but should have said 470kHz. Later sets used 455kHz. But if you're using the Velleman signal tracer (K7000?), then that probably makes little difference at this stage.
